/*
 * Copyright (C) 2014 Lucid Wolf
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.lucidhex.equation;

import java.util.HashMap;

/**
 *  
 * @author Lucid Wolf
 */
public class VariableMap {
    private double epsilon = 1E-5;
    private HashMap<String, Variable> variables = new HashMap<>();
    public void setEpsilon(double epsIn){
        epsilon = epsIn;
    }
    public Double change(String name, double aValue) {
        Double out = null;
        Variable v = variables.get(name);
        if(v != null && equal(aValue,v.value())){
            out = new Double(v.value());
            v.setValue(aValue);
        }
        return out;
    }
    public Double add(String name, double aValue) {
        Double out = null;
        Variable v = variables.get(name);
        if(v != null){
            out = new Double(v.value());
            v.setValue(aValue);
        }else{
            variables.put(name, new Variable(name, aValue));
        }
        return out;
    }
    private boolean equal(double a, double b) {
       return (Math.abs(a - b) <= epsilon);
    }
    public Variable getVariable(String name){
        Variable out = variables.get(name);
        if(out != null){out = out.clone();}
        return out;
    }
}
